May 14, 2014 1630 UTC Day 1 Convective Outlook
Updated: Wed May 14 15:42:33 UTC 2014 (20140514 1630Z Day 1 shapefile | 20140514 1630Z Day 1 KML)
Probabilistic to Categorical Outlook Conversion Table
Categorical Graphic
20140514 1630 UTC Day 1 Outlook Graphic
Probabilistic Tornado Graphic
20140514 1630 UTC Day 1 Tornado Probabilities Graphic
Probability of a tornado within 25 miles of a point.
Hatched Area: 10% or greater probability of EF2 - EF5 tornadoes within 25 miles of a point.
Probabilistic Damaging Wind Graphic
20140514 1630 UTC Day 1 Damaging Wind Probabilities Graphic
Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point.
Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
Probabilistic Large Hail Graphic
20140514 1630 UTC Day 1 Large Hail Probabilities Graphic
Probability of hail 1" or larger within 25 miles of a point.
Hatched Area: 10% or greater probability of hail 2" or larger within 25 miles of a point.
Risk Area (sq. mi.) Area Pop. Some Larger Population Centers in Risk Area
SLIGHT 280,472 41,427,454 Columbus, OH...Nashville, TN...Louisville, KY...Atlanta, GA...Cleveland, OH...
   SPC AC 141539

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1039 AM CDT WED MAY 14 2014

   VALID 141630Z - 151200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MID/UPPER OH VALLEY
   AND LOWER GREAT LAKES TO GULF COAST STATES...

   ...SUMMARY...
   ISOLATED SEVERE THUNDERSTORMS ARE LIKELY ACROSS PARTS OF THE LOWER
   MISSISSIPPI...TENNESSEE...AND OHIO VALLEYS THIS AFTERNOON INTO
   TONIGHT. DAMAGING WIND SHOULD BE THE PRIMARY HAZARD. HOWEVER...A FEW
   TORNADOES AND LARGE HAIL WILL ALSO BE POSSIBLE...ESPECIALLY FROM
   PARTS OF TENNESSEE AND KENTUCKY INTO FAR SOUTHEAST INDIANA...MUCH OF
   OHIO...AND WESTERN PENNSYLVANIA.

   ...SYNOPSIS...

   A HIGH-AMPLITUDE BLOCKING PATTERN WILL PERSIST OVER NORTH AMERICA
   THROUGH THE DAY ONE PERIOD WITH THE PRIMARY FEATURE OF INTEREST
   BEING A FULL-LATITUDE TROUGH LOCATED OVER THE CENTRAL PART OF THE
   CONTINENT. WITHIN THIS BROADER-SCALE PATTERN...A VORTICITY MAXIMUM
   AND ASSOCIATED 50-60 KT JET STREAK AT 500 MB WILL EJECT NEWD FROM
   THE BASE OF THE PARENT TROUGH THROUGH THE LOWER MS INTO OH VALLEYS
   IN ADVANCE OF AN UPSTREAM VORTICITY MAXIMUM DIGGING EQUATORWARD OVER
   THE UPPER MS VALLEY. THE GEOSTROPHIC RESPONSE TO THE FORMER
   VORTICITY MAXIMUM AND ATTENDANT 500-MB JET STREAK WILL BE MANIFEST
   IN THE FORM OF AN INTENSIFYING 850-700-MB WIND FIELD FROM THE MID
   SOUTH/TN VALLEY TO OH VALLEY LATER TODAY INTO TONIGHT.

   AT THE SURFACE...LOW PRESSURE OVER NRN MS WILL DEEPEN SLIGHTLY TODAY
   PRIOR TO UNDERGOING MORE SUBSTANTIAL INTENSIFICATION TONIGHT AS IT
   DEVELOPS NNEWD ALONG AN ASSOCIATED QUASI-STATIONARY FRONT TO NERN
   IND/NWRN OH BY 15/12Z. MEANWHILE...A TRAILING COLD FRONT WILL
   ADVANCE EWD THROUGH THE LOWER MS VALLEY AND CNTRL GULF COAST STATES.


   ...GULF COAST STATES TO MID/UPPER OH VALLEY AND LOWER GREAT LAKES
   THIS AFTERNOON INTO TONIGHT...

   12Z SOUNDINGS ACROSS THE PRE-FRONTAL WARM SECTOR INDICATE THE
   PRESENCE OF A MOIST AIR MASS CHARACTERIZED BY DEWPOINTS OF 60-70 F
   AND LOWEST 100-MB MEAN-MIXING RATIOS OF 11-13 G/KG. WEAK MIDLEVEL
   LAPSE RATES AND THE PRESENCE OF EXTENSIVE CLOUDS /AT LEAST ALONG THE
   IMMEDIATE SURFACE FRONTAL INTERFACE/ WILL TEMPER THE DEGREE OF
   DESTABILIZATION TODAY. WHERE STRONG BOUNDARY LAYER HEATING CAN
   OCCUR...AFTERNOON MLCAPE VALUES WILL APPROACH 1000-1500 J/KG.

   DCVA ASSOCIATED WITH VORTICITY MAXIMUM IN CONJUNCTION WITH A
   STRENGTHENING WAA REGIME ATTENDANT TO THE DEVELOPING LLJ WILL FOSTER
   AN INCREASE IN TSTMS ACROSS THE SLIGHT RISK AREA TODAY. LATEST
   CONVECTION-ALLOWING MODEL GUIDANCE SUGGESTS THE FORMATION OF A
   BROKEN CONVECTIVE BAND EVOLVING FROM THE VICINITY OF THE SURFACE LOW
   OVER WRN/MIDDLE TN SWD INTO MS/AL WITH ADDITIONAL...MORE RANDOM TSTM
   ACTIVITY INTENSIFYING BY AFTERNOON WITHIN THE WAA REGIME OVER
   KY/IND/OH.

   THE RESPONSE TO THE DEEPENING SURFACE LOW...AND TO A LESSER
   EXTENT...THE PRESENCE OF A BACKDOOR FRONT OVER WRN NY/PA INTO WV
   WILL RESULT IN VERTICALLY VEERING WIND PROFILES ACROSS THE WARM
   SECTOR WITH DEEP-LAYER SHEAR BECOMING SUFFICIENT FOR SUPERCELL
   AND/OR BOWING STRUCTURES. DAMAGING WIND GUSTS AND PERHAPS A FEW
   TORNADOES WILL BE THE PRIMARY HAZARDS...ESPECIALLY WITH STORMS
   FORMING NEAR AND AHEAD OF THE MIGRATORY SURFACE LOW WHERE LOW-LEVEL
   SHEAR AND FORCING ARE ENHANCED. THE TORNADO THREAT MAY BECOME MOST
   FOCUSED LATER THIS AFTERNOON INTO EVENING OVER CNTRL/ERN OH WHERE
   THE STRONGEST INSTABILITY COINCIDES WITH THE INCREASING VERTICAL
   SHEAR. HAIL POTENTIAL WILL LIKELY BE MAXIMIZED LATER TODAY OVER ERN
   PARTS OF OH/KY/TN WHERE STRONGER HEATING MAY YIELD GREATER
   DESTABILIZATION.

   WHILE DIMINISHING IN AREAL EXTENT...AT LEAST AN ISOLATED SEVERE
   THREAT WILL PERSIST INTO THE OVERNIGHT HOURS NAMELY OVER THE UPPER
   OH VALLEY OWING TO THE DYNAMIC FORCING ASSOCIATED WITH THE MIDLEVEL
   VORTICITY MAXIMUM AND DEEPENING SURFACE LOW.

   ..MEAD/LEITMAN.. 05/14/2014

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